| Champ: | Ivan Lendl |
| Runner: |  Pete Sampras |
| Score: | 5–7, 6–4, 6–4, 3–6, 6–3 |
| Draw: | 48 |
| Seeds: | 16 |
| Type: | singles doubles |
| Before Name: | Ebel U.S. Pro Indoor – Singles |
See main article: 1991 U.S. Pro Indoor. Pete Sampras was the defending champion.
Ivan Lendl won the title, defeating Sampras, 5–7, 6–4, 6–4, 3–6, 6–3 in the final.[1]